Electron-discharge device



y 7, 1929- R. v. L. HARTLEY 7 1,711,640

ELECTRON DISCHARGE DEVICE Fi1ed April 28. 1924 lawn/0r: lib/pl; L Ll/arlley Patented May 7, 1929.

UNITED STATES PATENT OFFICE.

RALPH V. L. HARTLEY, OF SOUTH ORANGE, NEVV JERSEY, ASSIGNOR TO WESTERN ELECTRIC COMPANY, INCORPORATED, OF NEVJ YORK, N. Y., A CORPORATION OF NEW YORK.

Application filed April 28, 1924.

This invention relates generally to means and a method for converting mechanical impulses into electrical impulses.

' ltis an object of this invention to convert mechanical vibrations into electrical vibrations, through the use of space discharge devices.

It is another object of the invention to provide a simple and G'l'llOlQIli; means for varying the impedance of a space discharge device in accordance with mechanical vibrations.

A further object of the invention is to utilize vacuum tube apparatus for electrically reproducing mechanical vibrations produced exteriorly of the tube in such manner as to set up variations in the intensity of the elec trical field in the tube to thereby eii'ect changes or impulses in the plate current which correspond to the mechanical vibrations originally produced.

An embodiment of the invention may include a vacuum tube device in which the space current is subjected to variations set up therein by mechanical movements in a control device mounted adjacent to the tube and on which the mechanical vibrations desired to be electrically'reproduced are impressed. The control, device includes a plate member external to the tube and so related to the anode of the tube as, when free to act, to neutralize or substantially neutralize the electrical field from the anode in the neighborhood of the filament. In order to control the action of the outside plate on the space current, a pair of grid members is mounted betweenthe outside plate and the tube, the grid members being movable relatively to each other in such manner as to bring the openings therein alternately into and out of mutual register or alignmentto thereby alternately liberate and obstruct the action of the outside plate on the electrical field within the tube. The controlling action thus produced by the grid members is preferably obtained by coupling the mechanical vibrated member to one of the grid members to vibrate the same.

In the drawing a single view in partly dia grammatic and partly sectional form illustrates an embodiment of the invention.

Referring to the drawing for a more de tailed description of the invention, an evacuated tube 1 is fitted with a filament 3 and an anode5 having lead-inconductors 7, 9 and 11 sealed in the lower wall of the tube. The lead-in conductors 7 and 9 of the filament are Serial No. 709,344.

included in a local filament circuit including a battery 13 and a rheostat 15. The lead-in conductor 11 of the anode 5 is connected to one side of an output transformer 17 and to the positive side of a battery 19 to which the filament lead-in conductor 7 is connected as at 21 in order to provide a difference of potential between the anode and the filament. it will be recognized that with the structural arrangement described a flow of electrons from the negative filament 3 to the positive anode 5 will take place when the filament is heated.

In order to vary the flow of electrons from the filament to the anode 5 in accordance with mechanical vibrations produced exteriorly of the tube, a control device including a plate and a grid structure 25 is mounted externally to the tube in a position to cause the filament 3 to occupy a position between the anode 5 and the outside plate 23. 1th this arrangement, and with the plate 23 connected through the conductor 26 to the negative side of the battery 19 so as to establish the plate at a negative potential with respect to the filament 3, it will be seen that a condition can be attained in which the electrical field due to the outside plate ..3 will,

when unrestricted in its action, neutralize or nullify the action of the field due to the anode and stop the flow of current in the output transformer 17.

Advantage is taken of the power of the outside plate 23 to influence the action of the anode, by interposing the grid structure 25 between the outside plate 23 and the tube and using the grid structure to control the action of the outside plate on the field within the tube. For this purpose the grid structure is made up of a fixed grid member 27 and a movable grid member 29 mounted in close and parallel relation to the fixed grid member. The movable grid member 29 is arranged to reciprocate in its own plane to which it is confined by the bearing members 31. Movement of the grid member 29 is effected through an operating connection at- 33 with a vibratory diaphragm 35 and it will be seen that the openings in the movable grid member will be moved into and out of alignment with the openings in the stationary grid member 27 as the movable grid member is vibrated. The effect of this is to permit the outside plate 23 to function when the openings in the two grid members are in mutual alignn'ient, or register, and to cut off the action 011 the electrical field within the tube of the field due to the outside plate when the openings are closed.

It will thus be seen that the mechanical vibrations of the diaphragm 35 are directly transmitted to the movable grid member 29 and that the vibrations of the movable grid member produce corresponding variations in the field in the tube, such variations being reproduced in the form of impulses or changes in the current delivered by the anode 5 to the output winding.

While the structure as thus described includes all the essentials for the purpose, it has been :tound that the presence of a grid mem ber 37 in the tube renders it possible to control the flow of electrons to the anode 5 with a smaller voltage on the outside plate 23 than would otherwise be necessary. Also the connecting of the inside grid member 37 and the outside grid structure to the battery 19 through the conductor 39 so as to produce a negative potential thereon with relation to the filament, prevents the accumulation of electrons on the glass wall of the tube and thereby increases the efliciency of operation of the device.

The vibratory diaphragm may be operated in any suitable manner in accordance with the use to which the device is to be put. For example, the device may be used as a sound transmitter in which case the vibratory diaphragm may be actuated by sound waves conveyed thereto through the receiver, 38.

What is claimed is:

1. In a device for converting mechanical vibrations into electrical vibrations, a vacuum tube,amember mounted externally to the tube, means for electrically charging said member and. means for controlling the effect of said member on the electrical field within the tube in accordance with mechanical. vibrations set up in said member.

2. In a device for converting mechanical vibrations into electrical vibrations, a vacuum tube, a member mounted externally to the tube and capable of being electrically charged, means mounted between said member and tube for varying the effect of said member on the space current of the tube, and means for controlling the effect of said first mentioned means in accordance with mechanical vibrations.

3. In a device for converting mechanical into electrical vibrations, a vacuum tube, a member mounted externally to the tube and capable of being energized to affect the electrical field within the tube, movable means mounted between said member and the tube for alternately cutting off the action of the member and permitting the energized memher to act on the tube, and means responsive to mechanical vibrations tor vibrating said movable means.

4. In a device for converting mechanical plate mounted externally to and adjacent the tube and capable of being energized to affect the electrical field within the tube, an apertured grid member mounted between said plate and the tube whereby the plate may act through the openings in the grid member to control the electrical field within the tube and means subject to mechanical vibration for varying the effective size of the openings in the grid member to produce corres onding variations in the operation of the tu 6. In a device for converting mechanical into electrical vibrations, a vacuum tube, a plate mounted externally to and adjacent the tube and capable of being energized to affect the electrical field within the tube, a stationary apertured grid member mounted between said plate and the tube whereby the plate may act through the openings in the grid member to control the tube, a movable member mounted adjacent the stationary rid member and adapted to be moved to afiernately cover and uncover the openings in the grid member, and means responsive to mechanical vibrations coupled to said movable member for operating the same.

7. In adevice for converting mechanical into electrical vibrations, a vacuum tube, a plate mounted externally to and adjacent the tube and capable of belng electrically charged to effect the electrical field within the tube, a stationary apertured rid member mounted between said late an the tube whereby the field due to t e plate may act through the openings in the grid member to control the tube, a movable grid member mounted adjacent to the stationary grid member and adaptcd to be vibrated in its own plane to vary the effective size of the openings in the grid member, and means responsive to mechanical vi- Brations for vibrating the movable grid mem- 8. In a device for converting mechanical into electrical vibrations, a vacuum tube containing an anode and a cathode, a source of current connected to the anode and the cathode in such manner as to provide a negative potential on the cathode and a positive potential on the anode, a plate mounted externally to and adjacent the tube and connected to said source of current so as to have a negative po-- the external plate may act to nullify the action of the anode, a stationary apertured grid member mounted between said plate and the tube whereby the plate may act through the openings in the grid member to control the action of the anode, a movable grid member mounted adjacent to the stationary grid member and adapted to be vibrated in its own plane to alternately cover and uncover the openings in the stationary grid member, and means responsive to mechanical vibrations for vibrating the movable grid member.

9. In a device for converting mechanical into electrical vibrations, a vacuumtube containing an anode and a cathode, a source of current connected to the anode and the cathode in such manner as to provide a negative potential on the cathode and a positive potential on the anode, a plate mounted externally to and adjacent the tube and connected to said source of current so as to have a negative potential with relation to the cathode, the ml ative positions of the plate and the anode being such that the cathode is located therebetween, a stationary apertured grid member mounted between said external plate and the tube whereby the external plate may act through the openings in the grid member to control the action of the cathode, a movable grid member mounted adjacent and parallel to the stationary grid member and adapted to be vibrated in its own plane to vary the effective openings in the grid member so as to control the effect of the plate on the electrical field within the tube, means responsive to mechanical vibrations for vibrating the movable grid member, and a grid member mounted in the tube between the anode and the cathode, said grid members being connected to said source of current so as to have a negative potential with relation to the cathode.

In witness whereof, I hereunto subscribe my name this21st day of April, A. D. 1924i. RALPH V. L. HARTLEY. 

